1. Field of the Invention
The present invention relates to flame retardant treating agents, to a flame retardant treating process and to flame retardant treated articles composed of polymer materials such as fibers or thermoplastic polymers which have been flame retardant treated.
2. Related Background Art
Various treating agents and treating processes have been employed in the past to impart flame retardance by increasing the flameproof properties of combustible or flammable fibers or plastics.
There are commonly employed (a) halogenated cycloalkane compounds as flame retarding components in flame retardant treating agents used in flame retardant treating processes whereby fibers are imparted with a flame retardant property and given more prolonged cleaning durability (durability against wet washing such as water washing, or dry cleaning). Also, (b) Japanese Unexamined Patent Publication SHO No. 60-259674 discloses a flame retardant treating process employing as the flame retarding component a mixture of a halogenated cycloalkane compound such as hexabromocyclododecane with a phosphonate compound.
For plastics, and particularly thermoplastic polymers, (c) salts of phosphinic acid are known as effective flame retarding agents (see German Patent Application Publications No.2252258 and No.2447727). More specifically, in European Patent Application Publication No.699708 there are disclosed calcium phosphinate and aluminum phosphinate as flame retarding components which are particularly effective for polyesters, and it is stated that deterioration of the properties of polymer molded materials can be reduced in comparison to using alkali metal salts.
For several polymers, (d) synergistic combinations of phosphinic acid salts and certain nitrogen-containing compounds are described in the International Patent Application PCT/EP97/01664 pamphlet, in German Patent Application Publication No.19734437 and in German Patent Application Publication No.19737727, which disclose that the flame retardance is increased compared to using phosphinic acid salts alone. For example, one of the synergistic agents may be melamine or a melamine compound (for example, melamine cyanurate or melamine phosphate), and although these by themselves can impart a certain level of flame retardance to some thermoplastic materials, their combination with phosphinic acid salts can exhibit an even more notable effect.